With many corporations and suppliers conducting development and validation tests at different Climatic Wind Tunnel sites, there is an increasing need for a recommended best practice that defines a process by which climatic wind tunnels can be correlated. This document addresses the test methods and metrics used to obtain similar results, independent of location, for Heating Ventilation and Air Conditioning (HVAC) and Powertrain Cooling (PTC) development. This document should be used as a guideline to make sure key aspects of tunnel testing are covered when comparing various climatic wind tunnel facilities.